Unfortunately, that won't do the trick. When I archive or file a conversation I expect the entire conversation to remain visually intact regardless of which mail client I use.
My current methodology is to allow a conversation to mature in the inbox then use a native Gmail property to archive/file the conversation. This preserves the labels and allow the appropriate portions of the conversation to appear in 'All Mail', 'Sent' and the names folder(s) in Aqua.
But sometimes I forget or the conversation resumes at some point after being archived/filed. If I then manage this conversation from within Aqua labels can (but don't always) become munged in a way where the conversation no longer appears under Sent. At some point this gets noticed and I then have to use a laborious process to reapply the 'sent' label without destroying the others. This can only be done in Aqua as none of the Gmail properties permit direct manipulation of the 'sent' label.
Hence the request for search function dedicated to FROM which will uniquely identify all items that I originated since I can no longer trust the sent folder/label.
Although I use conversations as an example the same thing can happen to an individual message - albeit much less likely.
I'm not trying to resurrect the earlier discussion or influence the 'priority' of this request. Just restating (consolidating) the background as it is spread over several posts in this thread.